Migrate ee/app/assets/javascripts/vue_shared/security_reports/components/split_button.vue to GlDisclosureDropdown or GlCollapsibleListbox

One or more dropdowns in ee/app/assets/javascripts/vue_shared/security_reports/components/split_button.vue should be migrated to one of the new dropdown components. See the parent epic &10695 for guidance on migration strategies.

Verification steps

1. Go to security-reports security pipeline, filtered on container scanning: https://gitlab.com/gitlab-examples/security/security-reports/-/pipelines/1026880640/security?reportType=CONTAINER_SCANNING
2. Click on a finding
3. Verify that the clicking the down arrow in the bottom-right button in the modal opens a GlCollapsibleListbox with options to "Resolve with merge request", "Download patch to resolve", (if no existing linked issue) "Create issue".